The present invention relates to apparatus for manipulating or advancing a tool, and more particularly to an apparatus for advancing a tool along a spiral path.
The present invention is particularly useful in manipulating and advancing a cutting tool in order to cut circular holes in a workpiece.
A problem encountered in cutting holes in a workpiece is in making the margin of the hole smooth around the entire circumference of the hole. The problem is how to begin cutting the hole without creating a discontinuity at the margin of the hole to accommodate the cutting tool itself, to begin the cutting operation. When using a mechanical cutting tool, such as a saw, a hole must be made in the workpiece to receive the saw therethrough. When using a cutting tool, such as a laser beam or high energy water jet, a hole will be initially made in the workpiece by the laser beam or water jet before the actual cutting operation begins. If this starting hole is at the margin of the final cut, it can create a blemish or discontinuity at the margin of the hole to be cut.
A solution is to begin the cutting operation inside the peripheral margin of the hole to be cut and then to advance the cutting tool to a location which will be the peripheral margin of the hole to be cut in the workpiece.
The present invention is also particularly useful in manipulating and advancing a cutting tool in order to cut a finished disc from a material stock.
The problem encountered in cutting a disc from a material stock is similar to that encountered in cutting a hole in a workpiece, that is, making the periphery of the disc smooth around the entire circumference of the disc. The problem is how to begin cutting the disc without creating a discontinuity at the periphery of the disc to accommodate the cutting tool itself.
A solution is to begin the cutting operation outside the peripheral margin of the disc to be cut out of the material stock.